Chlorine containing thermostabilized polymers

ABSTRACT

WHEREIN R1 AND R2 REPRESENT HYDROGEN OR LOWER ALKYL AND N IS 2 TO 6.   C6H(6-N)-(C(-R1)(-R2)-OH)N   THERMOSTABILIZED CHLORINE-CONTAINING POLYMER CONTAINING AS A THERMOSTABILIZING AGENT IN AN AMOUNT EFFECTIVE TO IMPROVE THE THERMOSTABILITY THEREOF, A POLYHYDROXAYALKYL SUBSTITUTED BENZENE OF THE FORMULA

United States Patent 3,763,096 CHLORINE-CONTAINING, THERMOSTABILIZED POLYMERS Egon Norbert Petersen, Neunkirchen-Seelscheid, Germany, assignor to Dynamit Nobel Aktiengesellschaft,

Troisdorf, Germany No Drawing. Filed Jan. 20, 1972, Ser. No. 219,499 Claims priority, application Germany, Jan. 27, 1971, P 21 03 678.2 Int. Cl. C08f 45/58 US. Cl. 26045.95 L 10 Claims ABSTRACT OF THE DISCLOSURE Thermostabilized chlorine-containing polymer containing as a thermostabilizing agent in an amount elfective to improve the thermostability thereof, a polyhydroxyalkyl substituted benzene of the formula wherein R and R represent hydrogen or lower alkyl and n is 2 to 6.

BACKGROUND The present invention relates to the stabilization of chlorine-containing vinyl polymers against degradation by heat.

Chlorine-containing organic polymers of high molecular weight, such as polyvinyl chloride and its copolymers, polyvinylidene chloride and copolymers thereof, and postchlorinated polyvinyl chloride, chlorinated polyolefins, etc., have to be stabilized against thermal decomposition for virtually all applications, even when they contain other additives, e.g., for the purpose of improving impact toughness or light stability.

The stabilization of polyvinylidene chloride and its copolymers is especially difficult. A considerable number of substances of many different classes of compounds have been proposed to improve the thermal stability of polyvinylidene chloride, such as epoxy compounds, phosphates, saturated and unsaturated alcohols, and polyhydroxyl compounds. Alkinediols, for example, have been proposed, either alone or in combination with other additives, as polyhydroxyl compounds to serve as thermostabilizers for polyvinylidene chloride (German Auslegeschrift 1,068,887, Brit. Pat. 764,233, W. German Pat. 802,893). Polyvalent saturated alcohols, such as tetraethyleneglycol, mannitol or sorbitol, are known as deactivators for iron compounds in the stabilization of polyvinylidene chloride (Swedish Pat. 122,576). Polyvalent aliphatic alcohols with up to 9 hydroxyl groups promote the HCl acceptor effect of epoxy stabilizers (U.S. Pat. 2,734,881).

Polyhydroxyl compounds such as trimethylolpropane and dipentaerythritol are particularly eifective components in stabilizer mixtures (German Auslegeschrift 1,190,659, French Pat. 1,399,240). Glycol ethers of glycerin, pentaerythritol or mannitol are said to have a thermal-stabilizing effect in polyvinylidene chloride even in the presence of iron (U.S. Pat. 2,459,746). Tertiary alcohols with up to 12 carbon atoms have already been claimed (U.S. Pat. 2,973,347).

On the other hand, no information is found on the use of aromatic compounds containing alcoholic hydroxyl groups as stabilizers for polyvinylidene halides.

THE INVENTION Now, the subject of the invention is thermostabilized, chlorine-containing polymers and copolymers, as well as 3,763,096 Patented Oct. 2, 1973 molding compounds made therefrom, which are characterized by the fact that polyhydroxyl compounds derived from benzene, having 2 to 6 hydroxyl groups in the a position to the benzene ring, and having the general formula R1 6 (6-n) +OH wherein R and R represent hydrogen or lower alkyl radicals and n represents the numbers 2 to 6, are used as thermal stabilizers.

The polyhydroxyl compounds of the invention are incorporated into the chlorine-containing polymers generally in quantities of 0.1 to 5%, preferably 0.25 to 2%, of the weight of the polymers.

The stabilizers of the invention can be used in combination with known thermal stabilizers, whereby a better stabilizing action is often improved than when either component is used alone, or the amount of both components can be reduced while achieving the same stabilizing action (see examples).

The action of the above-named compounds as thermal stabilizers is connected with the a position of the hydroxyl groups in relation to the benzene nucleus, and does not occur until there are at least 2 hydroxyl groups.

By lower alkyl radicals are meant those having 1 to 8 carbon atoms, preferably the radicals methyl-, ethyl-, n and i propyland the isomeric butyl radicals.

Preferred are the isomeric bis-(a-hydroxyalkyl)-benzenes, tris-(a-hydroxyalkyD-benzenes and hexa-(u-hydroxyalkyl)-benzenes, on account of their easy accessibility. The following are used advantageously:

1,4-bis- (hydroxymethyl) -benzene 1,4-bis- (a-hydroxyethyl -benzene 1, 3 ,5 -tris- (hydroxymethyl) -b enzene 1,2,4-tris- (hydroxymethyl) -benzene 1, 3 ,5 -trisa-hydroxyethyl) -b enzene 1,2,4-trisu-hydroxye'thyl) -b enzene 1,3 ,5 -trisa-hydroxya-methylethyl) -benzene hexahydroxymethyl) -benzene hexaot-hydroxyethyl -b enzene.

The preparation of the above-named compounds is well known to persons skilled in the art and can be performed by the cyclotrimerization of suitable alkinols (German Auslegeschrifts 1,159,951 and 1,468,677) or by hydrogenation of the corresponding diand triacetylbenzene,)among other methods (Am. Chem. Soc. 72 (1950) 2038 The stabilizers of the invention can be used alone or in mixtures with one another, and also in the form of mixtures of their stereoisomers or optical isomers.

By chlorine-containing polymers and copolymers in the framework of the invention are meant polyvinylidene chloride and its copolymers, polyvinyl chloride and its copolymers, chlorinated polyolefins and postchlorinated polyvinyl chloride, a chlorine content being the only limiting qualification. Chlorine-containing copolymers include those made from a chlorine-containing monomer and one or more additional chlorine-containing or non-chlorine-containing ethylenically unsaturated monomers such as vinyl acetate, vinyl propionate, ethylene, propylene, acrylonitrile, acrylic acid acrylic ester, methacrylic acid alkyl ester, esters of higher mono-unsaturated acids, vinyl ethers, etc. Also to be considered as chlorine-containing polymers are mixtures of polymers, both those of chlorine-containing polymers and copolymers together, and those of a chlorine-containing polymer with a non-chlorine-containing polymer, especially such as those which are added in the form of ethylene-vinyl acetate copolymers or copolymers or graft polymers of acrylonitrile, butadiene and styrene (ABS) or of methacrylic acid alkyl ester with butadiene and styrene (MBS) to improve the impact strength of manufactured products.

By molding compounds made from the named chlorinecontaining polymers and copolymers are meant those tech- The numerals 1 and 2 present minimal discoloration scarcely exceeding the natural color of the polymers.

In Table 1 the results are shown for a suspension copolymer consisting of 85% vinylidene chloride and 15% vinyl chloride (K value 49).

nically common preparations which contain, in addition TABLE 1 Quantity Diseoloration at 160 C. after- Stabilizer g z eit 0 min. min. min. 45 min. 60 minl 75 min. A Epoxidized soya oil (6.9% epoxy oxygen) i g g i g g g B Pentaerythritol- 0.? 13 2 1; 3-: :1; i g C Trimethylolpropane laurate 5 1 2 g 3 5-2 66 D Bisphenol-A-bls-(epoxypropane) g g i 4% g g E 1,3,5-tris-(a-hydroxyethyl)-benzene (=TEB) 0.? i g g g i g F Trimethylolpropane monolaurate with TEB added 2+0. 5 0-1 1 3 3 4 4 (3.... Bisphenol A-bis(ep0xypropane plus TEB) 1+0. 5 2 23 3 4 5 6 H 1:1 mixture of 1,3,5- and 1,2,4-tris-(hydroxy-methyD-benzene 1% 2 g Z 5 In each case 100 g. of vinylidene chloride copolymer was rolled together with 5 g. of acetyl tributyl citrate as Table 1 shows, in comparison to other thermostabilizers (A to D) the superior action of the stabilizers of the invention (E to H) which in the same quantity produce a better effect than prior-art stabilizers.

As it will appear from E and F, the addition of quantities of l and 1.5 wt.-percent does not make the action substantially better than the addition of 0.5 wt.-percent, and comparison with A to D shows that even smaller quantities of the stabilizers of the invention produce better action than larger quantities of the prior-art stabilizers.

Table 2 lists the thermostabilities determined on a vinylidene chloride-vinyl chloride copolymer of a weight ratio of 77:23 (K value 56). The test temperature was 150 C since the test films melt at higher temperatures.

TABLE 2 Quantity Discoloration at 150 C. afteradded, Stabilizer percent 0 min. 15 min. 30 min. min. 60 min. min. min.

A Epoxidized soya oil (6.9% epoxy oxygen content) g g 3 i i 2 g 0.5 1-2 2 3 34 4 5 B 1,3,5-tris-(a-hydroxy-ethyl)-benzene 1 1 1-2 2 3 3 4 1.5 1 1-2 2 3 3-4 4 (3...- 1:1 mixture of 1,3,5- and 1,2,4-tris'(a-hydroxyethyD- t; g if i Z g l h (h th l-eth 1)-benzene 2 2 3 4 4.5 5 D 1,3, ns-( y Y- y Y 1 1 1-2 2 3 4 4 plasticizer, 0.3 g. each of ethylene diamine distearate and calcium stearate, plus the amounts of stabilizer specified in Table 1, for a period of 10 minutes at -150 C. on nickel roller, to produce a sheet material 0.3 mm. thick.

The test films thus produced were tested for thermostability by a static test in which they were hung in an oven at C., specimens being taken every 15 minutes and examined for discoloration.

The discoloration was judged on the basis of the following scale:

0=colorless 1-=pale yellow According to Table 2 again, very small additions of 0.5 wt. percent of stabilizers according to the invention excel the action of the prior-art stabilizer (A) even though the latter was added in larger quantities.

Example 2 =yenow Table 3, and rolled for 10 minutes at C. into 0.3 3=brownish yellow 4=brown 65 The results of the thermostability testing (stat1c oven 5=dark brown test) performed as in Example 1 but at C. are shown 6=black in Table 3.

TABLE 3 Quantity Diseoloration at 190 C. aiter-- added, Stabilizer percent 0min. 15 min. 30 min. 45 min. 60 min. 75 min. 90 min.

N o stabilizer 1 1-2 2 34 5 6 6 Epoxidized soya oil o g 0-5 1 1-3 2 2 3-: g g 1,8,5-tris-(whydroxyethyl)-benzene 1 0 (H 1 2 3 4 5 Example 3 A suspension polymer of 85% vinylidene chloride, vinyl chloride and 5% acrylic acid methyl ester having a K value of 45 was rolled into test films 0.3 mm.

wherein R and R represent hydrogen or lower alkyl and n is 2 to 6.

2. Composition according to claim 1, containing 0.1 to 5 wt. percent of said agent based on the Weight of the thick together with 0.3% calcium stearate, 0.3% ethyl- 5 P l/ i I enediamine distearate, 5% acetyl tributyl citrate and the Composltloll accofdlng to 6131111 1, Contalnlng amounts of stabilizer listed in Table 4 and subjected to 10 2 Percent of said agent basfid 011 the Weight of the the static oven test at 150 C. The discoloration values polymer. are compared in Table 4.

TABLE 4 Amount Discoloration at 150 C. after added, Stabilizer percent 0min. min. 30 min. 45 min. 60 min. 75min. 90 min.

Bisphenol A-bis (epoxy-propane) (approx. 8% epoxy oxygen 2 2 2-3 8 3 4 4 5 Epoxidized soya oil 2 2 2-3 3 3-4 4 5 5 1,3,5-tris(a-hydroxyethyD-benzene 9 g g i i 0.5 1 1-2 2 3 3-4 4 5 1:1 mixture of 1,3,5- and 1,2,4-tris-(hydroXymethyD-benzene 1 0-1 1 1-2 2 2-3 3 4 1.5 o-1 1 1-2 2 2:3 3 34 Polymer mixtures of chlorinated PVC (62 wt. percent 4. Composition according to claim :1, said agent being Cl) and PVC (K value 65) in Weight ratios of (a) 90:10 at least one of the group: 1 and (b) 82:18 were stabilized in the same manner as in 1 4 bis (h o ydroxymethyD-benzene Table 4 an}? tested for therjmoztabrlrty at 170 C. The 1,4 bis (a hydroxyethylj benzene ts are t a same as m a e 1,3,5-tris-(hydroxymethyl)-benzene 1,2,4-tris-(hydroxymethyl)-benzene Examp 1e 4 l,3,5-tris-(a-hydroxyethyl)-benzene -h drox eth l)-benzene A suspension terpolymer of 88% vinylidene chloride, (a y y y 8% n-dodecylacrylate and 4% n-butylacrylate (K value 1153,5428};a'hydrogyia'methylethyl)'benzfine 48, Vicat temperature 83 C.) was rolled together with y rgxymet y Hgenzene 5% acetyl tributyl citrate, 03% calcium stearate and roxyethyn' enzene' 0.3% ethylenediamine distearate plus the stabilizers 0f 5. Composition according to claim 1, said polymer Table 5, at a temperature of 140 C. to form test films being vinylidene chloride polymer. 0.3 mm. thick. The oven test was performed at 160 C. 6. Composition according to claim 1, said polymer and gave the results shown in the following table. being vinyl chloride polymer.

TABLE 5 Anolurt Discoloration at 160 C. aftera e Stabilizer percent 0min. 15min. 30 min. min. min. min. min.

'lrirnethylolpropane mono-laurate 2 1 1-2 2 2-3 3 4 45 Epoxidized soya oil 5 g 2 Z g 'lrimcthylolpropane mono-laureate plus 1,3,5-tris-(a-hydroxycthyl)- benzene. 2+0. 5 (H 1 1-2 2 2 3 3-4 0.5 0-1 0-1 1-2 3 3-4 4-5 5 1 ,3,5-tris (a-hydroxy-ethyl)-benzene L g t; '3 g 2 i 2 0 0 1-2 1 2 a a-4 1,3,5-tris(whydroxy-zz-methylethyl)-benzene 5 i i 5 2:: g g 1,-bis-(a-hydroxyethyl)-ben zene '3 i g g i As it appears from Table 5, the stabilizers of the inven- 7. Composition according to claim 1, said polymer tion are especially well suited to copolymers on the basis being chlofiniiltfid p pof vinylidene chloride and acrylic ester. P H aceordlng to cla m 1, said polymer By suspension polymer, copolymer or terpolymer is belng P05tch19Y 1nated P YY Y chlofldemeant a polymer polymerized in aqueous medium where- 55 Composltlon aCCOTdIQg to Clam} 1, Sa1d P yin the monomer is finely divided and the polymerization F a copolymer 0f yh ne Chl ride and vlnyl chlocatalyst is dissolved in said monomer.

What is C1aimedis 10. Composition according to claim 1, said polymer 1. Thermostabilized chlorine-containing, organic poly- 2:2 a copolymer of vmyhdene chloride and acrylic mer composition comprising at least one of a polyvinyli- 0 References Cited dene chloride polymer, a polyvmylchlorrde polymer, a chlorinated polyolefin polymer, and a postchlorinated UNITED STATES PATENTS polyvinyl chloride polymer, in admixture, as a thermo- 3,062,895 11/1962 Martin et al. 2606l8 stabilizing agent in an amount effective to improve the 3,267,145 8/ 1966 Lund et al 2606l8 thermostability thereof, at least one polyhydroxyalkyl 5 3,0 2,882 11/ 1962 Parris 260--618 ubstituted benzgne of the formula Mikeska et a1. 3,030,427 4/1962 Earhart et al. 260618 3,022,355 2/1962 Earhart et al 260-618 2,542,417 2/1951 Kleinschmidt 260--6l8 FOREIGN PATENTS R) 797,054 6/1958 Great Britain. DONALD E. CZAJA, Primary Examiner I ia 75 V. P. HOKE, Assistant Examiner 

